EFFECTS OF A TOXIN ISOLATED FROM AUSTRALIAN TIGER SNAKE (NOTECHIS-SCUTATUS-SCUTATUS) VENOM ON AUTONOMIC NEUROMUSCULAR-TRANSMISSION

被引:14
作者
HARRIS, JB
ZAR, MA
机构
[1] Department of Pharmacological Sciences, University of Newcastle upon Tyne, Newcastle Upon Tyne
关键词
D O I
10.1111/j.1476-5381.1978.tb08467.x
中图分类号
R9 [药学];
学科分类号
1007 ;
摘要
The effects on mammalian autonomic neuromuscular transmission of a purified toxin from the crude venom of the Australian tiger snake, Notechis scutatus scutatus, have been investigated. The toxin had no measurable effect on transmission in either the rat anococcygeus, the rat vas deferens, or the longitudinal muscle of the guinea‐pig ileum. The toxin induced a contraction of longitudinal smooth muscle of the ileum. The tissue relaxed in spite of the continued presence of the toxin, and remained insensitive to further doses. The contractile response was not mediated by either cholinergic or histaminergic mechanisms. The toxin caused an inhibition of the response to field stimulation of the guinea‐pig vas deferens and the guinea‐pig seminal vesicle. The inhibition was spontaneously reversible, and the preparations remained insensitive to further doses of the toxin. The effects of the toxin were not mediated by either prostaglandins or by noradrenaline. The inhibitory effects of a variety of compounds known to act at presynaptic sites were also blocked by exposure to the toxin; inhibition caused by postsynaptic activity was unaffected by the toxin. It is suggested that the toxin inhibits transmission in the guinea‐pig vas deferens and seminal vesicle by a presynaptic mechanism. The possibility that the mechanism involves phospholipase A2 activity is discussed. 1978 British Pharmacological Society
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页码:349 / 358
页数:10
相关论文
共 22 条
[1]  
AMBACHE N, 1970, J PHYSIOL-LONDON, V208, pP30
[2]   EVIDENCE AGAINST ADRENERGIC MOTOR TRANSMISSION IN GUINEA PIG VAS DEFERENS [J].
AMBACHE, N ;
ZAR, MA .
JOURNAL OF PHYSIOLOGY-LONDON, 1971, 216 (02) :359-&
[3]   NON-CHOLINERGIC TRANSMISSION BY POST-GANGLIONIC MOTOR NEURONES IN MAMMALIAN BLADDER [J].
AMBACHE, N ;
ZAR, MA .
JOURNAL OF PHYSIOLOGY-LONDON, 1970, 210 (03) :761-+
[4]  
BELL PMG, 1971, J PHYSIOL-LONDON, V218, pP5
[5]   EFFECTS OF TAIPOXIN AND NOTEXIN ON FUNCTION AND FINE-STRUCTURE OF MURINE NEUROMUSCULAR-JUNCTION [J].
CULLCANDY, SG ;
FOHLMAN, J ;
GUSTAVSSON, D ;
LULLMANNRAUCH, R ;
THESLEFF, S .
NEUROSCIENCE, 1976, 1 (03) :175-&
[6]  
EAKER D, 1975, PEPTIDES CHEM STRUCT, P17
[7]   EVIDENCE FOR AN ALPHA-RECEPTOR AND BETA2-RECEPTOR MEDIATED INHIBITION OF TWITCH RESPONSE IN GUINEA-PIG VAS-DEFERENS BY NORADRENALINE [J].
EULER, USV ;
HEDQVIST, P .
ACTA PHYSIOLOGICA SCANDINAVICA, 1975, 93 (04) :572-573
[8]  
EULER USV, 1969, ACTA PHYSIOL SCAND, V77, P510
[9]   IMPORTANCE OF PHOSPHOLIPASE-A2 IN PROSTAGLANDIN BIOSYNTHESIS [J].
FLOWER, RJ ;
BLACKWELL, GJ .
BIOCHEMICAL PHARMACOLOGY, 1976, 25 (03) :285-291